In the past, LCDs have been used in a wide variety of environments, including displays within the cockpit of an aircraft. Avionics applications often impose stringent demands on the optical performance of LCDs. The need for cross-cockpit viewing requires high contrast often extending to a horizon viewing angle range of nearly +60.degree. to -60.degree.. Accommodating pilot height and head movement often requires a vertical field of view having a range extending from -5.degree. and +30.degree. from a normal line from the display surface. Display of high information content imagery, such as weather radar, often requires that the low gray levels be stable in both luminance and chromaticity. This is often difficult, especially at high vertical viewing angles.
Various compensation schemes have been proposed in the past, including those described in U.S. Pat. No. 5,504,603 by Winker et al. and entitled "Optical Compensator For Improved Gray Scale Performance In Liquid Crystal Display", issued on Apr. 2, 1996; U.S. Pat. No. 5,594,568 by Abileah et al. and entitled "LCD With a Pair of Retardation Films on One Side of Normally White Liquid Crystal Layer" issued on Jan. 14, 1997; U.S. Pat. No. 5,638,197 by Gunning, III et al. and entitled "Inorganic Thin Film Compensator For Improved Gray Scale Performance In Twisted Nematic Liquid Crystal Displays and Method of Making" issued on Jun. 10, 1997; U.S. Pat. No. 5,895,106 by VanderPloeg et al. and entitled "NW Twisted Nematic LCD With Negative Tilted Retarders on One Side of Liquid Crystal Cell" issued on Apr. 20, 1999, and described in the publication "Cockpit Displays V: Displays for Defense Applications" by D. B. Taber, L. G. Hale, B. K. Winker, W. J. Gunning III, M. C. Skarohlid, J. D. Sampica, and T. A. Seder, published in Volume 3363 of SPIE as part of the proceedings of a conference held on Apr. 15-17, 1998, in Orlando, Fla. by The International Society of Optical Engineering.
While these LCDs may have many advantages in particular uses, they also have significant drawbacks. One common drawback of these designs is the relatively high cost of such compensation systems. The use of proprietary techniques to manufacture some of the components of these LCD systems often leads to relatively high costs.
Consequently, there exists a need for improved methods and apparatuses for compensating LCDs.